Improvement in machinery tor preparing wqoden blocks for pavement



dem fst-'fea stwtdtjire;

WILLIAM `O. ROBBINS AND CHARLES W. STAFFORD, 0F NEW "YORK, N.

Letters Patent No. 97 ,554, dated Decemberll', 1869.

IMPROVBMENT 1N MACHINERY FOR PREPARING WQQDEN BLocKs lvonremmmmv'r.V

The Schedule referred to in these Letters Patent and making part of the same.

To vall 'whom it 'may concern.

Be it known that we, WILLIAM O.RoBB1Ns and CHARLES W. STAFFORD, of thecity and State of New York, have invented, made, and applied to use a certain new and useful Improvement inv Machinery for Preparing Wooden Blocks for Pavements; and we do hereby declare the following to be a full, clear, andv exact description of the said invention, reference being had to the annexed drawing, makingr part of this speciiicatiou, whereinv Figure 1 is a plan of the machine complete. Figure 2 is a cross-section of the machine, att-11e line x fr, showing the dovetail-cutters, as acting inthe wood. y Y

Figure 3 is a perspective view of a section of" pave-1 ment, invelted,showing the grooves cntin the same for the reception of keys or wedges.

Similar marks of referencev denote .the same parts.

This machine is-for the purpose ofcutting, into the underside of wooden pavement-blocks, dovetail grooves, to receive keysthat hold the blocks together, and form sections for paving streets.

The wooden blocks a af, to be grooved, are previously prepared4 hycutting dovetail grooves in their sides, and introducing keys, as seen at b b, figs. 2 and3; then the section thus keyed together is grooved upon its under surface, as at c c, to receive keys running at right angles to the keys b b, so as to tie all the yblocks oi' the section together inthe most rlu manner.`

Our invention relates to the peculiar construction of the tools employed fornmingdovetail grooves, and also to the mechanism that is' combined therewith, for

holding thejsection of paving-blocks, and presenting them to the action of the grooving-tools.

In the drawingv ll is the frame, carrying the shaft e, driven by competent power, from which belts pass to the vertical spindles f, upon the upper ends of which is a head, with cutters lil at the top, and on the sides are cutters o. The shape and size ot eachl oi' these heads are such, that the cutter or cutters t' desclibe a circle, whose diameter is equal to the width vof the. bottom surface of the dovetail groove c, and the edges 0f the cutters o are inclined, so as to dress o the interior inclined l surfaces of theV dovet-ail groove. v i

The cutters o are made movable, so as to set them out as they'are Worn byI sharpening, and the cutters i are made single, or in pairs, on each head, the cutting-edges being made like the section of -a crosseutsaw, to give a smooth bottom tothe groove, as the cutters revolve with great rapidity.

The spindles f are placed at the proper distance apart, to groove the ranges of blocks, and the step of each spindle is made adjustable, so as to be raised or lowered by the screw 2, to cut a deep or shallow groove.

Upon the topof the frame d, a slide-trame is tted, composed ofthe side pieces g, cross-pieces h, and longitudinal rack-bar k.

The rack of this bar is operated upon by a pinion uponthe shaft l, that receives motion either by a crank on said shaft, or the gear-wheels n, from the shaft'p.

Thesection of paving-blocks is laid with its edges `upon the side pieces g, as seen by red lines, fig. l, and there secured by the clamp-bar q and nuts r.

This operation brings the section of' paving-blocks to a level, and removes any wind that may have resulted from the introduction of the keys b.

The section of paving-blocks might nowhe moved along over the revolving heads and spindleslf, so as to groove the same upon the under surface, (as at c.) We, however, prefer and employ a series of revolving toolsto first rough out the groove, and ,leave the cutters t' and o the less labor oi' finishing the groove.

The roughingtools may he revolving cutters t, made -of chisels bolted upon stocks, or drunken saws, u u, may be employed to saw a kert` suiliciently wide to leave the cutters t' and o only the work oflinishing the dovetail portion of the groove, and dressing the' bottom thereof.

The frame that carries the .section of paving may be moved along, and then back again, and stopped, for removing one section and placing in another.

The springs 3 serve to raise and release the clamp q, when the nuts are released.

What we claim, and desire to secure by Letters Patent, is-

'lhe vertical cutters and spindles j' yi, and horizontal 

